In recent years, cloud computing has become popular as a system having a form different from a computer system of the related art. The cloud computing is classified into a SaaS (Software as a Service), a PaaS (Platform as a Service), and an IaaS (Infrastructure as a Service) depending on the provided service. In the cloud computing, management of resources is important for enhancement of availability and reliability, and for achievement of flexibility for system extension, and hence various kinds of research and development have been conducted.
The cloud computing of the IaaS is provided by a computer system in which a server and a storage are connected to each other. PTL 1 and PTL 2 are provided as literatures disclosing technologies relating to the availability of the server and the storage. PTL 1 discloses a technology of achieving a high availability (HA: High Availability) of the server in the IaaS. PTL 2 discloses a technology of achieving a high availability of the storage in the IaaS.